Multimedia Playing Media demo is not working

[ambitiousCC]

I wrote my own demo based on the example to test the QtMultimedia library. But it doesn't work, in onMediaStatusChanged I found mediaplayer.mediaStatus = MediaPlayer.InvalidMedia。

Window {
    id: root
    width: 800
    height: 600
    visible: true
    Rectangle {
        id: backVideo
        width: root.width
        height: root.height
        anchors.fill: parent
        z: -1
        color: "yellow"
        MediaPlayer {
            id: mediaplayer
            audioOutput: AudioOutput {}
            videoOutput: videoOutput
            source: Qt.resolvedUrl("http://xxx:xxx/test.mp4")
            onPlaybackStateChanged: {
                if (mediaplayer.playbackState === MediaPlayer.StoppedState) {
                    mediaplayer.play()
                }
            }
            onMediaStatusChanged: {
                console.log("media status changed")
                if (mediaplayer.mediaStatus === MediaPlayer.NoMedia) {
                    console.log("no media")
                } else if (mediaplayer.mediaStatus === MediaPlayer.LoadingMedia) {
                    console.log("loading")
                } else if (mediaplayer.mediaStatus === MediaPlayer.InvalidMedia) {
                    console.log("invalid")
                } else {
                    console.log("other status")
                }
             }
        }

        VideoOutput {
            id: videoOutput
            anchors.left: parent.left
            anchors.right: parent.right
            anchors.top: parent.top
            fillMode: VideoOutput.PreserveAspectCrop
            height: parent.height
        }
    }

    Component.onCompleted: {
        mediaplayer.play()
    }
}